Geotechnical and Geochemical Properties of Residual and Termite Reworked Soils within the Premises of the Polytechnic Ibadan, Southwestern Nigeria

Abstract

Three representative samples each from residual and termite reworked soils were collected within the premises of The Polytechnic Ibadan, southwestern Nigeria. Their suitability for construction purposes was determined by assessing their geotechnical and geochemical properties. Geotechnical tests carried out include moisture content, specific gravity, Atterberg limits, particle size distribution, compaction, UCS test and CBR. AAS was used to analyze the oxides composition of the soils. Both soil types were classified as low – intermediate plasticity clays with liquid limit between 25.5%-43.1%. The CBR values ranged from 80% – 85% and 20% – 50% for termite reworked soils and residual soils respectively. UCS ranged from 212.1KPa – 226.3 KPa and 191.7KPa – 200.0 KPa for the termite reworked and residual soils respectively. The OMC and MDD values for termite reworked soil ranged from 5.8% – 8.4% and 1968 kg/m3 – 2020kg/m3 respectively and between 12% – 15.2% and 1800 kg/m3-1940 kg/m3 for residual soils. Geochemistry result shows that the termite reworked soils contained a mean of 60.1% SiO2, 31.05% Al2O3, 1.7% CaO and 4.9% Fe2O3 while the residual soils contained a mean of 59.8% SiO2, 28% Al2O3, 1.6% CaO and 4.6% Fe2O3. This accounts for the better geotechnical properties exhibited by the termite reworked soils.